On Thursday, investigators inspect the roof of a Lord & Taylor where a surveillance camera, center, could be crucial in the investigation. / Julio Cortez, AP

by Jayne O'Donnell and Hadley Malcolm, USA TODAY

by Jayne O'Donnell and Hadley Malcolm, USA TODAY

If retail video cameras helped authorities identify suspects in the Boston Marathon bombing, it would be only the latest non-retail crime that store surveillance helped crack.

Video from Boston Lord & Taylor cameras was among footage examined by investigators as they tried to identify possible suspects.

Lord & Taylor would not comment other than to say that it was fully cooperating. But Joseph LaRocca, a retail security expert, says large retailers in urban areas typically have closed-circuit TV cameras that pan and tilt to capture activities outside the stores.

"The cameras will move around and zoom in on people and incidents of interest," says LaRocca of loss-prevention firm RetailPartners in Los Angeles. And retailers regularly turn video over to police when it is requested or if they detect criminal activity in or outside their stores, he says.

The January 2011 Tucson shooting of former U.S. congresswoman Gabrielle Giffords and others outside a Safeway supermarket was captured clearly on the store's video, says Richard Kastigar, investigations chief for the Pima County Sheriff's department, who reviewed it.

Footage showing convicted gunman Jared Loughner enter the store with another man raised the prospect of an accomplice until the man was determined to be the cab driver who brought Loughner to the store. Video showed Loughner placing plugs in his ears before walking outside. The expression on his face "showed the determination of the shooter" and "what his intent was" as he walked from victim to victim, Kastigar says.

The case underscored that retail video can be critical for investigators, prosecutors and juries, Kastigar says. "One of the first things we do is a 360 assessment as to what potentially might be around a crime scene taking video," he says. "We don't know where all the cameras are, but when there's a convenience store or other business and even some homes, the likelihood of video cameras is great."

Retail surveillance gear can be so sophisticated that cameras can record as far as half a mile away, says Rich Mellor, vice president of loss prevention at the National Retail Federation.

Store cameras have helped in investigations including child abductions, robberies, drug deals and car thefts, Mellor says. Last year, cameras at stores including Costco and Walmart captured drive-by purse-snatchings in which victims were dragged and injured.

"This is a really important aspect of what retailing does," Mellor says. "There are crimes that are solved every day as a result of their video equipment."

Some retailers go even further than cameras. Target has its own forensics lab where it analyzes video or fingerprints related to retail crime and often helps law enforcement with other cases not necessarily related to the retailer, says spokeswoman Jessica Stevens.

Many consumers, however, don't realize just how often their movements are being recorded and there are larger questions about the expanded uses of such surveillance, says Marc Rotenberg, executive director of the Electronic Privacy Information Center.

"It is possible to collect an enormous amount of information about people doing nothing suspicious," says Rotenberg, also a Georgetown University law professor. "There's a difference between a focused and a dragnet-style surveillance."

There should be a "meaningful evaluation of its effectiveness" of public surveillance, he says: "It's still very much an open question."